that carbon suit is NOT coming completely from the burned OIL ... ALL DFI engines have that Problem !

1) from the EVAP System there is always a Little bit of oil and condensate transfered into the engines combustion area .... BUT the intake valves were the cold parts of the engines valvetrain so the oil and condensate CAN PHYSICLY NEVER burn to ashes at the cold intake valves ! !

2) the DFI process is creating lots of carbon suit during the combustion and during the nessesary valve overlap .. were INTAKE and EXHAUST valves BOTH open and covered with the carbon suit ... BUT the exhaust valves get HOT enough to burn the carbon suit ... so at all DFI engines you see dirty intake valves and not so dirty exhaust valves !

3) all old style intake manifold injection engines clean the INTAKE valves automaticly by the fuel spray into the cylinder ... old Technology .. but cleaner Intake valves !

Good examples you find around the world in all Forums about DFI engines ... here a 98kmiles driven Golf TFSI :

We have a LLT with 64k miles on it with a RX catchcan on since nearly day one....absolutely NO intake valve coking.....and we see the results daily.

Yours is about the cleanest I have seen at that mileage except the one, that is how most look.

Here is a link to pictures submitted by techs from every DI engine in the world pretty much (including motorcycles) and with over 12,000 of the RX cans in use there are hundreds of members here that can show the results.

99% plus of the valve coking is a direct result of the oil ingestion via the PCV dirty side, and if you use a oil separating catchcan that actually catches and traps all, or nearly all the oil, then you have zero issues (again, hundreds of members here can remove there intake manifolds and show this).

Now, install the average can and 99% of them let 1/2 or more of the oil still pass through (no matter the name brand) so you have only 3-4 on the market that actually do trap all, or nearly all the oil.

If you click on this thread, part way down the page are most of the cans people buy today with cut aways or disassembled to show what is (or is not )inside of them plus a explanation of the testing results of what percentage pulls through most cans and why they do, or don't work well.http://www.camaro5.com/forums/showth...=265217&page=3

Pretty much the RX, Elite, and Saiku Micchi are the ones that trap all or nearly all (no, Elite does not pay me a commission, I report the actual testing and the results).

In the days of port injection, running a top tier fuel would keep the intake valves (and the area of the port the spray makes contact wife) clean. Look at a shell commercial to see the pictures of a old port injection engine valve run on a cheap fuel VS their techron.

Now with direct injection, no fuel touches the intake valves...only the air charge passes it so there is no difference in running a top tier vs a cheap (all come from the same bulk freighters here at the port of Manatee near us and the end user (shell, mobil, etc.) add the additives before delivery to the station).

So, as long as you have 1-2 qts of oil ingesting through the dirty side of the PCV system, you will always have the severe valve coking we see on ALL DI engines. Audi's V8 does have a secondary port injector to help eliminate the low RPM hesitation inherent with DI, but it only slightly reduces the coking.

You can also see the results of running a RX catchcan vs no can, or even one of the cheap ebay ones (or an expensive billet can with a poor design allowing oil pull through):

Anyone with a LS3/L99, remove your TB and look inside your IM and see what is ingesting. This car came the next day after delivery from the dealer:

Picture of SC and housing using a RX catchcan from day one for 16,000 miles VS a intercooler after 14,000 miles w/no can:

Scouring on pistons from carbon breaking loose:

Oil ingestion causes buildup on the piston rings and ring lands preventing them from moving freely to properly seal...resulting in loss of power and excess oil consumption:

Actual pictures from GM TSB:

Intake from LLT on left w/can from new, right w/out:

On any FI engine, the detonation caused by the oil ingestion results in a good deal less power than the same one with the oil ingestion stopped.

And, for those that delete the PCV systems function, then engine damage and premature wear is the result.

As part of the combustion process there is a good deal of pressure, or "blow by" that gets past the piston rings into the crankcase, and this is made up of several damaging compounds that if not evacuated while still in a gaseous, or suspended state, will condense and settle into the engine oil and on the internal parts when the engine cools down after shut down.

These consist of water, unburnt fuel, abrasive carbon particles (many to small for the oil filter micron size to remove and trap so they continue to circulate with the engine oil wearing your engine prematurely), sulfuric acid (which etches the crank & cam journals and bearing surfaces once they reach a certain PPM) and other damaging hydrocarbons, etc.

A PEM PCV system uses the intake manifold vacuum to evacuate these damaging compounds while the clean side provides filtered metered fresh air to make up for what is evacuated.

Ideally you want filtered fresh air entering one bank of the engine (on the V6 it is the rear of the drivers side valve cover) where it passes the valve train, is pulled down into the crankcase, all the while flushing the damaging compounds out with it while they are still suspended any time the engine is running. They then travel up the passenger side bank, past the valvetrain and out the rear of the passenger side valve cover where the intake manifold vacuum pulls the compounds into the combustion chamber to be burnt and further burnt clean in the catalytic converter. The issue is the oil most pulled in with this.

Now, if you delete this function, or break this flow (by just adding breathers to release pressure or take the clean side and dirty side and run both lines into a single can, you then are only relieving the pressure. Every time the engine is shut down and cools, all these damaging compounds condense and fall into the oil where they cannot be removed without changing your oil and the concentration accumulates and increases with every start up and shutdown. That can shorten engine life by 1/2 to 1/3rd what it would live with proper evacuation.

Also, every street legal gasoline car and light truck sold in the US today has a functioning PCV system that evacuates and flushes the crankcase for long engine life.

ANY deletion or disabling of this function will result in premature wear and is also grounds for any manufacturer to void a warranty when such an important system is disabled.

A proper catchcan system simply installs inline on the dirty side to trap this oil mist causing all the issues and does not effect the evacuation process......but far to often we see those that do not understand this aspect of the PCV system and only think of the obvious...the crankcase pressure.

So, you do NOT want oil in the intake air charge. You do NOT want to delete or disable the PCV systems evacuation process with a separate clean side source and a dirty side. You NEVER want to mix the clean and dirty sides (this defeats the PCV systems function, and you can stop all, or nearly all intake valve coking with one of the few truly functional cathcans on the market.

And there is so much misinformation and misunderstanding of the PCV systems functions, that you do well to study all I have posted here.

Anyone wanting more actual pictures, etc. just ask....and this is a typical letter/email/message we get from those that do install the RX can:

Hey Tracy, Just wanted to thank you, and everyone at RevXtreme. I bought a catch can from you, for my 2005 CTS. Well since installing it i'm not consuming any oil anymore. I've had a close eye on the oil level since i have installed it and it hasn't used a drop. I don't know how or what that catch can has done to prevent the oil consumption. (I've read your tech tips article and understand the concept of how a catch can work.) I guess i am just baffeled that it something so simple like that could work.

Anyway just wanted to thank you. I was at my last wits end with this car and was about to put it back on the market, after the dealer replaced two motors under warrenty.

I'll be purchasing another catch can from you in the future. I have a 2000 Camaro SS that is getting a turbo as we speak, as a fun project street car.

But thanks again. It was definetly worth the wait.

Gabe Moulden

This customer was lucky that the gummed up ringlands were able to free themselves after adding the can and stopping the oil ingestion....something that we see only app 50% of the time.

A proper catchcan will also eliminate the need for a seafoam or upper induction cleaning ever if installed when new.

We see on average 1-3 MPG improvement with a good can as the detonation caused by the oil ingestion is no longer present so the ECU/PCM can keep the ignition timing at the optimum level.

We have many small fleet owners as customers (AC/plumbing, etc.) that have them installed just for the fuel savings, not for extended engine life.

12 years of manufacturing these and over 12,000 in use around the world.

So Tracy in other words you are strongly disagreeing with ASH's assertion that the carbon buildup on the valves is from combustion by products (e.g. carbon soot)???

When I have looked at the pics of other LLT and LFX engines that HAVE NOT had Seafoam or BG 44K treatments, the valves appeared "wet" with oil. That makes me believe the buildup is from the ingested oil, not combustion by products.

But what do I know? I'm an electrical engineer, not a mechanical or chemical engineer.

100% sure. This is my field of expertise for over 38 years, and the oil puddles in the intake show it all. Also, the fuel system evap emmissions only draws in fuel vapors...they burn clean.....but read all in detail and the links to back it all up.

Since they are not allowed to attack the turbo and supercharger solutions we develop this seems their next tactic. But it is pretty embarrassing to be that clueless on something so well documented for so many years by so many (such as the University of Maine study and all the TSB's from all auto manufacturers).

I want no fight, no attacks.....just all do what we do best and offer the most accurate and correct info possible with the documentation to back it up.

There is no place for drama on this or any forum IMHO. The market is huge for all.

100% sure. This is my field of expertise for over 38 years, and the oil puddles in the intake show it all. Also, the fuel system evap emmissions only draws in fuel vapors...they burn clean.....but read all in detail and the links to back it all up.

Since they are not allowed to attack the turbo and supercharger solutions we develop this seems their next tactic. But it is pretty embarrassing to be that clueless on something so well documented for so many years by so many (such as the University of Maine study and all the TSB's from all auto manufacturers).

I want no fight, no attacks.....just all do what we do best and offer the most accurate and correct info possible with the documentation to back it up.

There is no place for drama on this or any forum IMHO. The market is huge for all.

But yet you can never see, that you are the one many times that cause it by saying crap like this. If you want to avoid the fights, then don't start them.

PLEASE just stick to the information you want to provide and dont START THE DRAMA.

I realize that threads like these tend to inevitably lead to discussion of what the cause of the intake coking is, and the validity and effectiveness of the available solutions or preventions.

I don't mind such discussions, but we're veering into the territory of accusations of posting intentionally misleading information in an effort to discredit a business competitor.

That kind of crap has no place in this thread, and will be reported.

For those of you reading this and other similar threads, as you read the information posted by some very knowledgeable folks here, take some of what's said with a grain of salt and use your judgement in assessing their positions and perspectives on the topic.

That said, personally, I believe there's some validity in both theorized causes being discussed here: 1) PCV-related vapors, and 2) reversion (which is the term for combustion chamber by-products fouling the not-quite-completely closed intake valves).

I think both contribute. To what extent, I don't know, and won't try to argue with those that claim they do.

But I do know that there's really only one of the two that I can do anything about.

Back to the topic at hand, I intend to Seafoam my engine within the next couple of days. Not sure how soon after I'll have time to tear down the intake again and check for the effectiveness of the Seafoam treatment. I need to do it on a day where I have time to manually clean the valves, if they still require it, because I don't know when I'll have time to tear it down for a third time. I'd like to kill two birds with one tear down.

Warning: Thought experiment ahead. I have no scientific/engineering proof whatsoever.

It strikes me that if there are combustion by-products making their way back out to the intake valve area due to partially open intake valves during the exhaust purge that the same by-products would be sucked back into the cylinder on the next downstroke due to the vacuum created.

But if the intake valve area was "wet" with condensed oil vapor, then the combustion by-products would have something to stick to and would not ALL be sucked back in.

If true, this sounds like a perfectly vicious circle that would account for all the buildup AND support both positions of our learned co-contributors.

Also if true the solution would be to avoid the condensed oil vapors in the first place.

Lastly a chemical analysis of the oil in the catch can versus that captured from the walls of an intake port would speak volumes as to the relative contribution of each "source".